Earthquakes & Volcanoes Unit 4: Tectonics NOTES page 3 ©Mark Place, 2008-2009 www.LearnEarthScience.com Revised 2010

Key Concepts & Questions What is the driving force behind crustal movement ? Convection Currents in the Mantle

Key Concepts & Questions What provides the energy for this force? radioactive decay

Key Concepts & Questions What are the different types of earthquake waves? And how do they travel?

Key Concepts & Questions p-waves Travel Through Anything primary waves push-pull waves

Key Concepts & Questions s-waves Travels Through Solids Only secondary waves shear waves

Key Concepts & Questions Where can most earthquake epicenters and volcanoes be found? at plate boundaries "Ring of Fire"

To find an earthquake’s epicenter a seismologist Key Concepts & Questions To find an earthquake’s epicenter a seismologist must have data from at least how many locations?

At least three

Key Concepts & Questions How can scientists infer the properties of Earth’s interior?

by observing earthquake waves

Remember: P-Waves go through everything Remember: P-Waves go through everything. S-Waves do not got through liquids-will not go through outer core, so outer core is a liquid.

How do scientists know that Earth’s inner core is solid? Key Concepts & Questions How do scientists know that Earth’s inner core is solid?

by the refraction (bending) of P-waves

Also meteorites from space contain solid iron & nickel Also meteorites from space contain solid iron & nickel. Scientists believe the Earth’s interior is also solid iron & nickel.

What can people do to protect themselves Key Concepts & Questions What can people do to protect themselves during an earthquake? get under desk/table stand against interior wall stay away from windows

Have an emergency evacuation plan. What can people do to protect themselves before an earthquake? Have an emergency evacuation plan. Prepare food and water. Build reinforced structures.

Key Concepts & Questions What is the Richter Scale and how is it used?

a measure of earthquake strength based on a scale from 1-10 Remember the new MERCALLI SCALE measures damage from I - XII

Earthquake Reference Table Questions Please get out your ESRT p. 11!

Interactive P & S Wave Chart p. 11

3600 kms If a p-wave arrives five minutes before the s-wave arrives, how many kilometers from the epicenter is a location? 3600 kms

4800 kms If a p-wave arrives at 12:10:00 and the s-wave arrives at 12:16:20, how many kilometers from the epicenter is a location? 4800 kms

9:04:20 An earthquake epicenter is 2600 kilometers from a location. If the p-wave arrives at 9:00:20, what time will the s-wave arrive? 9:04:20

1:13:20 An earthquake epicenter is 5200 kilometers from a location. If the s-wave arrives at 1:20:20, what time did the p-wave arrive? 1:13:20

3200 kms 4:40 later If a p-wave arrives 6 mins after an earthquake occurs, how many kilometers is the location from the epicenter? How long after the p- wave arrives will the s-wave arrive? 3200 kms 4:40 later

Plate Tectonics Tectonics NOTES page 6 ©Mark Place, 2008-2009 www.LearnEarthScience.com

What is the Theory of Continental Drift?

What is the Theory of Continental Drift? Alfred Wegener, 1915 The continents were once a super-continent called Pangea. the continents are plowing through the ocean floors---most people didn’t believe this

What evidence supports this theory? Africa & South America look like they fit together similar fossils, rocks, and glacial striations

What is the Theory of Plate Tectonics? Earth's crust is made up of plates that ride on top of the asthenosphere The plates move due to convection currents in the mantle

What evidence supports this theory? distribution of earthquakes and volcanoes sea-floor spreading

How do oceanic and continental crust compare with regard to thickness and density? (ESRT pg 10) Thickness (pg 10) high low thin thick

continental crust oceanic crust What are the primary rocks which make up the continental and oceanic crusts? continental crust oceanic crust Low-density, light- colored, coarse- grained, felsic, igneous rock High density, dark- colored, fine-grained, mafic igneous rock granite basalt

What are these types of plate boundaries? What are the key characteristics for each? Give an example of where each can be found.

oceanic-continental convergent boundary trenches, volcanoes, deep earthquakes Peru-Chile Trench

continental-continental convergent boundary mountain building Himalayas

transform fault slide past one another shallow earthquakes San Andreas Fault

divergent plate boundary new crust is made Mid-Atlantic Ridge

What happens to the age of oceanic crust as distance increases from a ridge?

Age increases as distance increases from the ridge.

same pattern on opposite sides of the ridge proves sea-floor spreading Explain how magnetic data can be used to show that oceanic crust is diverging at ridges. Use the diagram below to help explain your answer. as new crust is made at ridges, the ferrous minerals (Fe) align according to where the magnetic poles are located same pattern on opposite sides of the ridge proves sea-floor spreading